Push button operated master switch



Jan. 24, 1939. c. A. RASMUSSEN 2,144,665

PUSH BUTTON OPERATED MASTER SWITCH Filed Jan. 1Q, '1936 E Sheets-Sheet lF'IE- 2.

N E 5 S U M n R a... N m M ATTORN EY Jan; 24, 1939. c. A. RAsMUssEN2,144,565

PUSH BUTTON OFERATED MASTER SWITCH n Filed Jan. lO, 1956 2 Sheets-Sheet2 PIE VIR/6 T'IHN H HSHUSS E N INVENTOR ATTORNEY Patented Jan. 24, 1939UNITED STATES PATENT OFFICE PUSH BUTTON OPERATED MASTER SWITCH 3 Claims.

This invention relates to master switches adapted to control the currentsupply to electric motors by the medium of magnetic contactors, and moreparticularly to push button operated master switches.

Presently known master switches of the push button type embody aplurality of individual, independent push button switches, each of whichcontrols an individual circuit. It is well known, that the operation ofthese individual push button switches complicates the control of themaster switch and also necessitates a special cut-out switch, to permitof the current being cut off, when one or the other of theY push buttonswitches sticks or should get out of order.

The primary object of the present invention is the provision of asimplified push button operated master switch, having only two coupledpush buttons, each of which is adapted to control a plurality ofcircuits, the push buttons being coupled with each other to preventtheir independent operation.

Another object of the invention is the provision of a push buttonoperated master switch with two coupled push buttons, each of which isadapted to control a plurality of circuits, and with means forautomatically and simultaneously returning the push buttons to theirneutral position, when the buttons are released by the operator.

A further object of the invention is the provision of a simplified pushbutton operated master switch with two coupled push buttons actuating amulti-contact switch, which switch is adapted to control a plurality ofcircuits for multi speed forward and reverse rotation of a motor.

Still another object of the invention is the provision of a simplifiedpush button operated master switch with two push buttons actuating upona rotary switch drum adapted to control a plurality of circuits formulti speed forward and reverse rotation of a motor.

A still further object of the invention is the provision of a simplifiedpush button operated master switch with two push buttons, coupled witheach other and with a rotary switch drum adapted to selectively open andclose a plurality of circuits ior multi-speed forward and reverserotation of a motor, the switch drum being provided with means forautomatically rotating same and the push buttons coupled therewith toneutral position.

In addition the invention has certain other marked superiorities, whichradically distinguish it from presently known structures. Theseimprovements or superior characteristics embodying certainnovelfeaturesof construction arevset forth in the appended claims, and a preferredform of embodiment of the invention is hereinafter shown with referenceto the accompanying drawings forming part of the specification.

In these drawings:

Figure 1 is a front elevation of a push button operated. drum masterswitch according to the invention.

Figure 2 is a cross sectional view through the push button operated drummaster switch shown in Figure i, the section being taken on line 2 2 ofFigure 1.

Figure 3 is a longitudinal sectional view through the push buttonoperated drum master switch shown in Figure 1, the section being takenon line 3 3 of Figure l.

Figure 4 is a front elevation of the drum or cylinder of the push buttonoperated master switch.

Figure 5 is a cross sectional view through Figure 4, the section beingtakenvon line 5 5.

Figure 6 is a longitudinal sectional view through Figure 4, the sectionbeing taken on line 6 6.

Figure 7 is a cross sectional view through Figure 6, the section beingtaken on line 1 1.

Figure 8 is a wiring diagram for a magnetic reversing panel with fivespeed points and with a five position push button operated masterswitch, as shown in Figures 1-7, for the control of a slip ring motor.

Referring more particularly to the drawings, the push button masterswitch embodies a housing having a base 2, a middle portion 3 and acover 4, the base, the middle portion and the cover being rigidlyconnected to each other by means of screws 5 and 6 respectively. Thebox-shaped base mounts a bakelite or fiber plate l, which plate isrigidly secured to the base by means of screws 8, and this iiber platecarries two rows of spaced contact members 9, which members are attachedto said plate by means of screws I0. The contact members 9 areelectrically connected by means of leads I I with the net I2 and withthe contacts I3 of a magnetic reversing panel I4', which panel isprovided with iive speed points, see Figure 8. The Contact members 9cooperate with a rotatable switch drum I4, which drum is mounted torotate around a xed shaft I5, having its lower end I6 guided in a boreI1 in the middle portion 3 and its upper end I8 pinned to a bracket I9by means of a pin 20. The bracket I9, which is rigidly secured to thewall 2| of the middle portion 3 by means of screws 22 suspends the shaftI5 and prevents its rotation, so that the drum I4 is properly guidedduring switchingV operations.

freely rotate around the shaft I5 and the hub 'I'he drum I4, which ismade of bakelite or other suitable insulating material, embodies ahollow cylinder 23, having its open top and bottom portions closed byber discs 24, 25 respectively. The top disc 24 is provided with acylindrical extension' 24', supporting a gear 26, which gear is rigidlyattached to said extension by means of screws 2'I, so that the cylinder23, its top disc 24 and the gear 26 rotate jointly around the shaft I5,when the gear 26 is actuated upon by mechanism hereinafter to bedescribed. The outer surface of the cylinder 23 of the drum I4 carriestwo, substantially oppositely arranged contact segments 28, whichsegments are secured to the cylinder 23 by'means of screws 29. Thesecontact segments 28 cooperate with the contact members 9, when the drumI4 is rotated and thus permit of a plurality of circuits being openedand closed by rtation of the drum i4.

The drum i4 can be rotated in either direction against the torsionalforce of a spring 30, which spring tends to automatically rotate saiddrum to ar neutral position, in which the segments 28 and the ContactYmembers 9 are separated from each other and no current flows throughthe switch. This spring is sleeved upon Vthe elongated hub 3i of a disc32 having its hub lholds the spring 30 in proper position upon the hub3|. The disc 32 carries close to its peripheral edge an upwardlyextending post 35, which post ,is engagedat opposite sides by thelaterally extended free ends 36 and 3l of the spring 3i), when saidspring is under torsional tension, see Figure '7. The ends 36 and 3l ofthe spring 30 furthermore engage a post 38, extending downwardly fromthe gear 23. This post 38 is extendedthrough the top disc 24 of the drumi4 and so related to the post 35, that post 38 can 3i connectedtherewith without interfering with the upwardly extending post 35. Thepost 38, which terminates just above the disc 32, effects the rotationof the drum I4 against the torsional force of the spring 30, when thegear 26 is rotated in either direction by the mechanism now to bedescribed, and thus insures automatic resetting of the drum to itsneutral position at will of the operator. y

The operating mechanism for the gear 2S and therewith for the drum I4embodies two push buttons 39 and 4U, the push `button 39 effecting aleft-handed rotation of the drum and the push button lil effecting aright-handed rotation. of said drum. rI'hus the two push buttons carryat their lower ends rack bars 4I, 42 respectively, which bars aresymmetrically arranged with respectV to the gear 26 for cooperationtherewith. lThe rack bars 4I, 42 are guided in brackets 43, whichbrackets arev secured byv means of screws 44 to the middle portion 3 ofthe housing. The push buttons 39 and 43 extend through openings 45 inthe cover 4 to permit of these buttons being readily actuated upon bythe operator. It should be noted that these push buttons are coupledwith each other by the gear 26 and that therefore the operator, whenactuating one button,.simultaneously shifts the other button, as adownward movement of one button effects an upward movement of the otherbutton and viceversa. k

`The shape of the contact segments 28, which cooperate with the contactmembers 9 permitsA of five consecutive positions of the master switchfor forward and for reverse operation of a motor, as will readily beseen from an inspection of Figure 8. This figure shows diagrammaticallythe electric coupling of the five position push button Voperated masterswitch with a reversing magnetic panel having five speed points, thepanel being connected with a slip ring motor 46. Such magnetic reversingpanels being old in the art and rnot subject to this invention, atracing of the circuits for the diierent'speeds of the motor is thoughtto be superfluous and. therefore omitted, the diagram being merely shownto indicate an application of the master switch.

Multi-position push button operated master switches of the typeVdescribed are particularly adapted for manual control of motors inmachine tools, hoisting apparatus and so forth. When used'for hoistingapparatus these switches may be used with the so called stiff armcontrol of the carriage, as these switches can readily be attached toand suspended from the carriage by means of a stiff arm lever extendedfrom theV carriage. For pendent control, a wire cable, not

on the middle portion 3 of the housing, so as to release strain on theiiexible conduit tothe switch. A handle bar 48, arranged on .the cover 4just below the push buttons 39 and 40 permits of convenient operation ofthe switch.

Having thus describedmy invention, ,what I claim is: Y

1. A master switch for a stiff arm control hoist comprising a housing, ahandle bar extended from said housing parallel to the longitudinal axisthereof, reversible rotary switch mechanism insaid housing substantiallyin alignment with its longitudinal axis,rspring means holding saidVswitch mechanism yieldingly in neutral position,

and two push button means arranged side by side in rectangular relationwith respect to said spring means. Y

2. A master switch comprising a housing having a handle bar extendedfrom its upper front portion parallel to the longitudinal axis of thehousing, a shaft having one end rigidly secured to said housing insubstantial alignment with the longitudinal axis thereof, a control drummounted to freely rotate around said shaft, contact members secured tosaid housing and cooperating with said drum during switching operations,two push button means rectangularly related to said shaft extendedthrough said housing adjacent to each other just above and symmetricallyarranged to said handle bar, coupling meansconnecting said push buttonswith veach other and said control drum adapted to shift said drum toforward and reverse positions, and yieldingV means coupled with saidshaft and said drum for automatically and simultaneously shifting saiddrum and push button means to neutral position. Y 'Y 3.A A master'switchcomprising a housing having a chambered extension at its upper frontportion, a handle bar extendeddownwardly fromfl said chamberedextension, a stationary shaft extending through said housing parallel tosaid handle bar having one end rigidly secured to said housing, acontrol drum mounted to freely rotate around said shaft, contact memberssecured to said housing and cooperating with said drum during switchingoperations, two push button means extended through said chamberedextension adjacent to each other and symmetrically arranged to saidhandle bar, rack bars at the inner ends of said push button means, agear engaging said rack bars rigidly secured to the top of said controldrum for rotation therewith,

and yielding means Within said drum connecting said drum and shaft andpermitting rotary movements in opposite directions of said drum withrespect to said shaft, said coupling means holding said drum yieldinglyin neutral position and returning same automatically to its neutralposition after each rotary movement of said drum by said push buttonmeans.

CHRISTIAN A. RASMUSSEN.

